Bug 13621

Summary: Buildroot builds for i686 even though i486 is selected
Product: buildroot Reporter: moelzerjens
Component: OtherAssignee: unassigned
Status: RESOLVED MOVED    
Severity: normal CC: buildroot, yann.morin.1998
Priority: P5    
Version: 2021.02   
Target Milestone: ---   
Hardware: PC   
OS: Linux   
Host: Target:
Build:
Attachments: defconfig

Description moelzerjens 2021-03-17 14:19:03 UTC
Created attachment 8801 [details]
defconfig

Selecting i486 as target architecture variant results in a kernel that's built for i686.

Steps to reproduce:

Build a image with the attached minimal defconfig and run `qemu-system-i386 -nographic -cpu 486 -kernel output/images/bzImage` results in `This kernel requires an i686 CPU, but only detected an i486 CPU.`.
Comment 1 Peter Seiderer 2021-03-18 21:08:23 UTC
(In reply to moelzerjens from comment #0)

The buildroot kernel configure/make is called with the correct 'ARCH=i386' and
uses the kernel i386_defconfig without further specification of CPU type, which defaults from the linux kernel configure (see e.g. build/linux-5.11/arch/x86/Kconfig.cpu) to M686:

  choice
        prompt "Processor family"
        default M686 if X86_32
        default GENERIC_CPU if X86_64

For workaround specify the correct CPU either by configuring a custom linux kernel config/defconfig file (or configure by 'make linux-menuconfig')...

Maybe something which can be improved in buildroot..., on the other side a very special use-case ;-)
Comment 2 Yann E. MORIN 2024-06-15 14:56:45 UTC
Thank you for your report.

The issue tracker for the Buildroot project has been moved to
the Gitlab.com issue tracker:
    https://gitlab.com/buildroot.org/buildroot/-/issues

We are taking this opportunity to close old issues in this old
tracker. If you believe your issue is still relevant, please
open one in the new issue tracker.

Thank you!